Electric lamp



Oct. 22, 1935. H. F. TEICHMANN ELECTR IC LAMP Original Filed July 14.1933 Patented Oct. 22, 1935 UNITED STATES PATENT OFFICE llclahm.

The invention relates to electric lamps, and consists in a filamentstructure which is particularly adapted for service in a lamp whoseglass body or bulb is of polygonal form, such for example as thepolygonal lamp described in Letters Patent No. 1,972,541, granted to meSeptember 4, 1934.

The present practice is to form lamp bulbs 01' "frosted" or opaqueglass, inasmuch as such glass has the desirable characteristic ofeliminating the glare and softening the light of the glowing filamentwithin the lamp. While the usual lamp of any specified candle powerefliciently produces the light required of it, one may observe that theappearance of the lighted bulb itself is not attractive to the eye,chiefly because its filament is more or less concentrated in arelatively small locality within the bulb and produces unequaldistribution of light upon the exposed wall of the lamp. One region ofthe wall is brilliant and another dull. The object of my presentinvention is to provide a filament structure which is eilective toilluminate uniformly the "frosted" or colored walls of an electric lamp.

My above-noted patent explains wherein a polygonal lamp, say a lampwhose body is square in cross-section, possesses advantages which arevaluable in advertising displays and other installations. It is furthermy aim to provide a filament structure which in service, so far as ispractical, is particularly efiective in illuminating uniformly allexposed faces of a polygonal bulb, to the end that the lamps may be moreeifective, either severally or in group organization, and may be morepleasing in appearance.

The lamp of my invention includes other structural characteristics ofvalue. Whereas according to usual construction the filament of anelectric lamp is supported within the bulb by means of a glass stemconstructed of two glass members (known as the flare and the exhaust orsealingofif tubing), which two members are independently formed and thenassembled and united with the lead-in wires of the lamp, in my lamp thestem is a unitary thing which may be produced in a single glass-castingoperation, the lead-in wires being introduced to the body of the stemduring the casting process. Accordingly, my lamp may be moreeconomically constructed. And whereas, in the ordinary lamp the bulbmust be exhausted and its atmosphere determined before the basal membersor contact pieces of the lamp are assembled upon and permanentlyintegrated with the bulb, in my lamp the exhausting outlet of the lampis accessible in the base oi the finished lamp, and advantageously inthe unitary, cast glass stemof the lamp. Thus, in my lamp the atmospherewithin the lamp may be determined and adjusted after the lamp has beenmanufactured, and the lamp need not be discarded, as lamps of the usualstructure are discarded, when factory tests show that the atmospheresurroimding the filament is not what it should be.

In the accompanying drawing Fig. I is a view 10 in side elevation of theunit glass stem and filament structure of my invention, and illustratesin vertical section a polygonal bulb in position for assembly with thestem.- Fig. 11 shows, partly in side elevation and partly in verticalsection, a 15 view of the completely assembled lamp. Figs. III and IVare views in cross-section, taken respectively on the planes I1IIII andIV--IV of Fig. I. Figs. V and VB are fragmentary views in sideelevation, each illustrating a modification in the filament structure ofthe lamp. Figs. VI and VIII show the filament structures 01' Fig. V andVII, respectively, as they appear in development. And Fig. 1X is a viewin vertical section of the unit glass stem, and showing a modificationin structure.

The lamp of my invention comprises a polygonal bulb I which is unitedwith a glass stem 2. Four sets of supporting wires 3 are secured attheir lower ends to the glass stem, and extend upward substantiallythroughout the length of the bulb and in parallelism with itslongitudinal axis; the supporting wires carry filaments 4, and theterminals la of the filaments are connected to the lead-in wires 5 and6; and the lead-in wires severally make contact with the two poles orcontact pieces 1 and 8 which are secured in electric isolation from oneanother upon the assembled stem and bulb. As in the case of the usualelectric lamp, when my lamp is installed in an electric socket, electriccurrent fiows through the filaments l, causing them-t0 glow and producelight. Although the particular form of the contact pieces I and 8 is notessential to the practice of this invention, I have shown them to be oi.the form illustrated and described in my above-noted patenta form whichadapts the lamp for installation in a push-type socket.

The integral, die-pressed stem 2 comprises a head portion 2a, a baseportion 2b, and an intermediate body portion 20. A passage id isprovided in the body of the stem; the passage terminates at one end inan opening in the head 2a, andat its opposite end terminates in asealing-ofl tube 2e,locatedon the side ofthe stem between the bodyportion 20 and the base portion 212. Each of the lead-1n wires 5, 6 isembodied and sealed (for a portion of its length) in the stem 2; thelower end of lead-in wire 5 projects from the body portion 20 and in theassembled lamp makes contact with contact piece I, while the lower tipof lead-in wire 6 projects from the base portion 2b and is electricallyunited with the contact piece 8. The upper ends of the lead-in wires 5,6 project upward from the head portion of the stem and are electricallyconnected, in parallel, to the terminals of the filaments 4.

Advantageously, the several supporting wires 3 are each of elongateU-shape. The vertical legs of each U-shaped member are coiled atintervals, to provide loops 3a through which the filaments 4 areprojected, and by means of which, in the group organization of U-shapedmembers 3, 3, the filaments 4 are supported. At the bend or bottom eachU-shaped member is embodied or secured in the head portion 2a of theglass stem, so that a sturdy support is provided for the filaments,while manifestly providing for such expansion and contraction of thefilaments as occurs when the lamp is in service.

As already mentioned, it is characteristic of the stem 2 that it may beintegrally formed in a single glass-casting or pressing operation. Inaccordance with engineering practice an automatic machine may beprovided to insert and hold the portions of wires 5, 6 and 3, 3, to beembodied in the stem, in place within a matrix of required shape; a gobor blank of glass is placed in the matrix and pressed to the form ofstem 2; by means of a suitable core piece or piercer the passage 2d isprovided during the casting operation, so that the glass stem may befashioned, and its associated wires 5, 6 and 3, 3 may be embodied in it,in a single casting operation. The engineer will know how existingautomatic glass machines may be modified for the production of my glassstern, and in describing the invention it is needless to dwell furtherupon the apparatus employed. Suffice to say that, whereas the glass stemof the usual lamp is constructed of two or more preformed glass memberswhich are fused together and sealed upon the lead-in wires for the lampfilament, my stem 2 is in a single casting operation formed as a unitarything which includes the lead-in wires and supporting wires for the lampfilaments, and embodies a passage for exhausting the lamp, when the bulband stem have been united.

It will be understood that aside from departures noted in thisspecification, the lead-in wires 5, 6, the filaments 4, and thesupporting wires 3 will be constructed and embodied in the lampstructure in accordance with usual practice. For example, the filamentsmay be constructed of tungsten, the supporting wires of nickel, and thelead-in wires may comprise copper and platinum riphery of the laterallyextending, central body.

portion 20 of the stem are heated to the point of fusing, and then arepressed into welded union as indicated in Fig. II. Next a band of sheetcopper or brass is electrically united with the ter- -minal of lead-inwire 5 and cemented in place over the region of union of the stem andbulb,

to provide the contact piece I, and a jacket of such material is unitedwith the lead-in wire 6 and cemented upon the base portion 2b of thestem, to provide the contact piece 8. The assembly is made more secureby means of flanges la, 8a which are spun into the form and positionillustrated in Fig. II. The lamp is now completely assembled ready to beexhausted of air, and, if desired, charged with an atmosphere of inertgas, such as nitrogen. Here again the apparatus and methods in practiceto-day are employed; and it is sufficient to say that the air within thelamp is removed and inert gas introduced by way of the passage 211formed in the stem 2. When proper atmospheric conditions have beenestablished within the lamp, the tube 2e is heated and sealed-off(welded shut) in the usual manner. The lamp is now complete, and readyfor service.

It will be perceived that the outlet of the exhaust passage 2d islocated in the side wall of the glass stem, between body portion 20 andthe base portion 212; that is, in the completely assembled structure theoutlet is located in an open interval between the contact pieces I and 8of the lamp. Accordingly, the evacuating, charging, and sealing-off ofthe lamp may be done when the structure has been completely assembled.To be able to do this is of great practical value, inasmuch as the lampmay be inspected for mechanical imperfections during the various stagesof its manufacture, and, if any imperfections are found, the lamp may bediscarded before it is exhausted of air and charged with inert gas. Ofcourse, the practice prevailing to-day. is to provide the lamp with itsultimate atmosphere as soon as the bulb and stem are united, andthereafter to apply the basal portions and contact pieces to the lamp.Manifestly, if imperfections are then found in the assembled lamp, andindeed they often are, the loss is greater than it would be in theprocedure made possible by my invention.

The structure of my invention makes it possible at any time to adjust orchange the atmosphere within the lamp. Obviously, the sealed outlet ofthe passage M is accessible between the contact pieces I and 8, so thatheat may be applied to the seal. Thereupon the glass may be softened andentrance made into the passage. Thus, the gaseous conditions within thelamp may be regulated and the mouth of the passage again sealed-off. Thesealing-off provides a closure of welded glass over the mouth of thepassage 2d, which closure is superior to any sealing which may be had bya valve, or by cement. 5

Indeed, as evidenced by the lamps on the market, it is practicallyessential that the electric lamps for ordinary use be so sealed.However, in specialized cases it may be desirable to change theatmosphere within the lamp quite often, and in such cases the mouth ofpassage 2d need not be sealed-off, but may be plugged with a body (Fig.IX) of sealing Wax, lead or other suitable material which is imperviousto gases and which may be hardened in the mouth of the passage.

While (upon referring to Fig. II) it will be understood that the glassstem, the filament struc-v ture, and the contact pieces mayadvantageously be embodied in lamps of round cross-section, my stem andfilament structure per se is particularly adapted for lamps which arepolygonal in crosssection. In exemplaryway, Figs. I-III, I have shownthe bulb l to be square in cross section. The head portion 2a of thestem iscorrespondinglysquare'inplanandtheU-shapedfilammtmpports3,3aresolocatedandsecuredintheeornerregionsofthesquareheadportionthatthevertical legs of the U-shapedsupports comprise companion supportingwireswhichlie opposite or adjacenttothe respective edge portions lcolthe bulb.Thefilamentsl-inthiscaselshowfour resecuredatintervalstothefour U-shaped supports 3, 3; thefilamentsaredistributed axially of the bulb andthroughout its length; the two upper filaments are arranged closertogetherthantheothers,toinsurethattheendortopofthebulbwillglowwiththesamelightintensity as the remaining exposedwall portions :ofthebulb. Asmaybeseeninl'ig.IV,eachfilament 6 isapoLvsonal loop (an octagonal loop in this case) and the portions of theloop extending between the companion legs of the supports 3, 3 providefilament elements which are severally located opposite or adjacent tothe edges lc of the bulb,sothattheedge regionsofthebulbmay beilluminated with the same light intensity as the remainder of thepolygonal bulb.

Figs. V and VI illustrate a modification in the filament structure. Inthis case the filament supports are shown as comprising each a singlelength of wire 30 rising from a U-shaped base 3|, which base is embeddedin the head portion of the glass stem, in the manner already describedin connection with the supports 3, 3. A loop 32 is coiled in the upperterminal of each support 33, and the opposite legs of each U-shaped base3| are each formed to include hooks or catches 34. The filament 40, may,as it is shown in Fig. VI, comprise a single length of tungsten wirewhich is passed through the loops 32 in the four supports 33 and hookedbeneath the catches 3. The terminals of the filaments are, of course,united with the lead-in wires 5, 6.

Still another modification is shown in Figs. VII and VIII. The filamentsupports 33. in this modification correspond in general with thestructure described in Fig. I, and the chief distinction is found in theorganization of the filaments carried by the supports. That is to say,the companion legs of the U-shaped supports 3" are provided with loops300a, and a filament wire is wound zigzag through the loops of eachsupport; that is, each filament is of angular serpentine form, as shownin Fig. VIII. The oppodte ends of the zigzag filaments are united withcollector wires Ill and 80, whence communication is established with thelead-in wires 5, 6. Indeed, the collector wires 10, Ill may themselvesbe filament elements.

It will be understood, therefore, that I have provided a structurehaving filament portions which are particularly effective upon the edgeregions of a polygonal bulb, to the end that all wall portions of such abulb may glow with substantially uniform light intensity. And I haveprovided a unitary glass stem which may be produced as a single casting,whereby advantages of the nature indicated are obtained in largestmeasure.

I claim as my invention:

1. An electric lamp comprising a polygonal bulb, a stem of glass sealedin the mouth of said bulb, a plurality of supporting wires secured tothe head of said stem, filaments carried by said supporting wires, whichfilaments are distributed axially of the bulb and include portions thatare located opposite and adjacent the edges of said bulb, whereby inservice all exposed faces of the bulb are illuminated with substantiallyuniform intensity, two contact pieces secured in isolation from oneanother upon the assembled stem and bulb, and lead-in wires extendingthrough the glass body of said stem, and severally connecting saidcontact pieces with the terminals of said filaments.

2. An electric lamp comprising a polygonal bulb, a unitary cast stem ofglass including leadin wires sealed in the mouth of said bulb, a passagein said stern terminating at one end within, 10 and at the opposite endwithout said bulb, a plurality of supporting wires secured to the headof said stem, filaments carried by said supporting wires, whichfilaments are distributed axially of the bulb and include portions thatare located opposite and adjacent the edges of said bulb, the inner endsof said lead-in wires being secured to said filaments, and two contactpieces secured in isolation from one another upon the assembled stem andbulb, which contact pieces are severally united with the outer terminalsof said lead-in wires.

3. An electric lamp including a bulb, a stem sealed in the mouth of saidbulb, and contact pim secured upon the assembled stem and bulb, thecombination of a filament structure comprising companion supportingwires secured at their lower ends to said stem and extending inparallelism with the axis of said bulb, a zigzag filament extending withand secured at intervals to said companion supporting wires, and lead-inwires connecting the terminals of said filament with said contactpieces.

4. A stem structure for an electric lamp including a bulb. a filament,filament-supporting means, and contact pieces, said stem comprising aunitary cast body of glass including lead-in wires, a head on said stemadapted to secure said filament-supporting means, a base on said stemfor the reception of a metal contact piece, and a spaced body portionintermediate said head and base and adapted for welded union with thebulb of said lamp.

5. A stem structure for an electric lamp including a bulb, a filament, afilament support, lead-in wires, and contact pieces, said stem structurecomprising an unitary body of glass cast and sealed upon said lead-inwires, means at the top of said body for securing said filament support,means at the opposite end of said body adapted to receive a contactpiece, an intermediate body portion adapted for welded union with saidbulb, and an exhausting passage formed in said cast body of glam, saidpassage terminating at one end above and at the opposite end below theintermediate portion of said stem body which is adapted for said weldedunion with the bulb.

6. A stem structure for an electric lamp including a bulb, a filament, afilament support, lead-in wires, and contact pieces, said stem structurecomprising an unitary body of glass cast and sealed upon said lead-inwires, said cast body of glass also embodying a portion of said filamentsupport and said support projecting from said body, said cast glass bodycomprising a body por-- tion adapted for fused union with said bulb, andan exhausting passage formed in said cast body of glass, said passageterminating at one end above and at the opposite end below the bodyportion of said stem which is united with said bulb, and in assemblysaid bulb and stem supporting said contact pieces in electric isolationfrom one another and severally in union with said lead-in wires.

7. An electric lamp comprising a polygonal bulb, and a glass stemincluding lead-in wires sealed in the mouth of said bulb, a supportingwire located opposite and adjacent each edge of said bulb, whichsupporting wires are secured at their lower ends to said stem, filamentscarried by said supporting wires and including portions particularlyeffective for the illumination oi. the edges of the bulb, and contactpieces secured in isolation from one another upon the assembled stem andbulb, which contact pieces are severally connected with the oppositeterminals of said filaments by means of said lead-in wires.

8. An electric lamp comprising a polygonal bulb, a stem sealed in themouth of said bulb, contact pieces secured in isolation from one anotherupon the assembled bulb and stem, and independent filament loopsconnected electrically in parallel and supported at intervals axially ofthe bulb, said loops being severally of relative great compass withrespect to the axis of said bulb, and said loops including portionslocated adjacent the edges of said bulb, whereby the edges of said bulbare adapted to be illuminated with substantially the same lightintensity as the remaining wall portions of the bulb, and the terminalsof said loops being connected in parallel to the respective contactpieces.

9. A stem structure for an electric lamp, comprising a unitary cast bodyof glass, said body of glass including a head portion, a base portion,and an intermediate body portion spaced from said head portion andadapted for welded union with the bulb of said lamp, and an exhaustingpassage formed in said body of glass, said passage terminating at oneend above and at the opposite end below the said intermediate bodyportion.

10. In an electric lamp including a bulb, a filament, a filamentsupport, lead-in wires, and contact members, the combination of aunitary stem molded and sealed upon said lead-in wires, said stemincluding a spaced portion at one endtor mounting said filament supportsin said bulb, said stem including at its opposite end a spaced portionprojecting from said bulb for the support of 5 contact member, and saidstem being secured in the mouth of said bulb by sealed engagementbetween the wall of the bulb and the body portion of the stem locatedintermediate said opposite ends, and an exhausting passage terminatingat 10 its one end above and at its opposite end below said intermediatebody portion or the stem.

11. An electric lamp comprising the combination of a glass bulb having arelatively wide and thin-lipped mouth, a filament within the bulb, is

electric lead-in means for said filament, and a base, said basecomprising an integral, unitary, die-pressed body of glass including abody portion for closing the mouth or said bulb, said body portion beingof relatively greatlateral extent with 20 respect to the axis of saidbulb and including an outer peripheral edge of relatively small thickness with respect to the lateral extent oi. such mouth-closing bodyportion, said outer peripheral edge of said body portion being securedin welded 5 union with the thin lip 01' said mouth, said electriclead-in means projecting through and being hermetically sealed in saidunitary, die-pressed base within or inwardly of the compass of saidperipheral edge, a passage formed in said base, 30 and a die-shapedsealing-off tube integrally formed with said base and being accessiblebelow said mouth-closing body portion thereof, said passagecommunicating at its upper end with the interior of said bulb andterminating at its lower end in said sealing-oil tube, whereby, uponproviding desired atmospheric conditions within the bulb, said passagemay be readily sealed.

HENRY F. TEICIMAN'N. 0

